1. Field of the Invention
The present invention relates to semi-automatic weapons and methods and kits for modifying the weapon so it will no longer operate semi-automatically and will require, after each firing, a manual operation to reload the weapon.
2. Description of Related Art
In a common semi-automatic rifle, a bolt carrier is slidably mounted inside an upper receiver that fits in a lower receiver that may have a trigger, pistol grip, and butt stock. A charging handle on the upper receiver can be used to retract the bolt carrier and load a live round before releasing the bolt carrier, allowing it to move forward into the firing position. Upon firing, exhaust gas tapped from the barrel is fed back through a gas tube to impinge upon a key on the bolt carrier to drive it backwardly. This motion automatically ejects the spent cartridge and then feeds another live around, before the bolt carrier returns to the firing position.
In a semi-automatic weapon the trigger must be pulled once each time a round is fired. In a fully automatic weapon such as a machine gun, the trigger is pulled once and multiple rounds of ammunition are fired in rapid succession until the trigger is released. Title II of the Federal firearms laws highly regulates fully automatic weapons. As an example, the M-16 military rifle has been produced with a fully automatic capability, although some versions have selective fire and can operate semi-automatically or in bursts.
Semi-automatic weapons with certain features mimicking the M-16 rifle or other military weapons are defined as “assault” weapons (e.g. the AR 15 rifle).
Weapons with some of those disfavored features have been banned in a number of states, and were temporarily banned on the Federal level. These disfavored features include high-capacity or detachable magazines, forward grips, barrel shrouds, bayonet lugs, threaded muzzles, and military-style pistol grips and butt stocks.
Some of these disfavored features may be considered reasonable for sporting and hunting purposes. In any event, the owners and prospective purchasers of such assault rifles (or handguns) are reasonably concerned that these weapons will be declared illegal or will become subject to intrusive regulations.
Accordingly, there is a need to adapt certain weapons to accommodate existing laws or foreseeable changes in the laws.
Referring to FIG. 1, a conventional semiautomatic weapon 14 is shown partially disassembled. Lower receiver 48 includes a trigger 48A, grip 48B, butt 48D, and receptacle 48E. Bolt 50 is placed in the forward end of bolt carrier 16. Carrier 16 has on top and in front a conventional key 52. Bolt carrier 16 is slid into the rear opening 42A of upper receiver 42. Gun barrel 20 is attached coaxially to the front of upper receiver 42. Upper receiver 42 has a mounting collar 42B, and barrel 20 has a mounting collar 54.
Upper cowl 30 and lower cowl 31 connect together to form a conventional hand guard (together referred to as hand guard 33). Cowl 30 has on top a series of parallel projections 30A forming a conventional Picatinny rail. Each of the projections 30A has a short stub supporting a plate with tapered, wedge-shaped edges. Similar parallel projections 30B on the right of cowl 30 also act as a Picatinny rail. Lower cowl 31 has on its underside a series of projections 31A and on the left a series of projections 31B, both sets of projections also acting as a Picatinny rail. Picatinny rails are well known for mounting accessories such as a rifle scope, handgrip, etc. In some cases a Picatinny rail may be formed from a rectangular plate having a face with rectangular parallel ridges running between right and left edges that are tapered and wedge-shaped.
Hand guard 33 mounts into collars 42B and 54 to form a sleeve that encircles barrel 20 and gas tube 18. The back end of gas tube 18 is shown slid into socket 52A of key 52. As shown in FIG. 5A, the forward end of gas tube 18 is inserted into gas port 56A of component 56 and held in place by pin 18A. Port 56A communicates through channel 56B to vent 32 in barrel 20.
When semiautomatic weapon 14 is assembled, the user may pull back a charging handle 57, which retracts bolt carrier 16 and bolt 50 in well-known manner. A conventional mechanism in lower receiver 48 will then load a round of ammunition (not shown) into upper receiver 42 in front of bolt 50. When this retraction reverses, bolt carrier 16 is driven forward by a spring (not shown) to thrust the ammunition into the breech of barrel 20, which is then closed by bolt 50. When trigger 48A is pulled a hammer (not shown) in lower receiver 48 strikes a firing pin (not shown) in bolt 50 to fire the ammunition so that combustion gas drives a bullet (not shown) through barrel 20.
When this bullet passes vent 32 the exhaust gas is fed through channels 56B and 56A into gas tube 18. This very high pressure gas impinges against bore 52A (FIG. 5A) in key 52, driving bolt carrier 16 rearwardly. This rearward kinetic energy is used to strip the spent cartridge (not shown) and eject it out of receiver 42 before automatically loading a fresh cartridge in front of bolt 50. Bolt carrier 16 is then returned by spring pressure to load the new round of ammunition in the breech of barrel 20 and close bolt 50 in the breech.
When trigger 48A is next pulled exhaust pressure in tube 18 causes the foregoing cycle to repeat, with bolt carrier 16 and bolt 50 retracting, ejecting the spent cartridge, and returning to load a fresh round of ammunition into the breech of barrel 20. This semi-automatic cycle occurred without the need to operate the charging handle 57. Another cycle can be initiated by firing another round, once again sending combustion gas through tube 18 to retract bolt carrier 16, strip the spent cartridge, before loading a new round, and driving bolt carrier 16 into a charged position ready for firing.